How is the winner of the lottery chosen?

If your talking about the huge multimillion dollar lotteries then everyone buys tickets each with a number on them and each week the lottery company chooses a new number and if your ticket says that exact number then you won.

If the lottery is won off of scratch tickets it depends on the number found on the ticket (and you try to scratch off those same numbers)

The winner of the lottery is chosen from a ticket with pencil scribbles on it. It's what you pick out of the black box